Progressive forming machines typically shape a piece of round wire, hereinafter sometimes called a blank, into a desired shape by striking it with tools and forcing it into dies having configurations corresponding to intermediate and finally shaped blanks or parts. Depending on the character of the part, this forging process can involve separate forging blows performed at multiple successive work stations. Hex head or twelve point head bolts are examples of parts commonly produced in progressive forging machines that can suffer when a blank turns even slightly on its longitudinal axis when it is transferred from one work or forming station to another. Where the blank has a profile that is not both circular and concentric with its axis, rotation of the blank about its longitudinal axis can introduce enough misalignment to prevent the blank from being properly received and formed in a succeeding workstation. This unintended turning, even if relatively small, can result in a misshapen part.
In a high production application, particularly where the unwanted turning of a blank occurs randomly and intermittently, a defective finished part may not be detected by the manufacturer. However, even a small number of defective parts mixed in with a large batch of good parts can cause significant problems for the ultimate user of the part. It can be expected that these problems and their associated costs will ultimately be traced back to the manufacturer resulting in customer dissatisfaction as well as ultimate financial loss to the manufacturer that far exceeds the value of the defective part.